### Correct Option: A. Polyethylene terephthalate (PET) #### Detailed Explanation: **1. Understanding the Properties of PET:** Polyethylene terephthalate (PET) is a type of polyester that is widely used in the production of plastic bottles and containers. The key properties that make PET suitable for this application include: - **Strength:** PET has a high tensile strength, which means it can withstand significant force without breaking. This is crucial for bottles that need to hold liquids under pressure (like carbonated beverages). - **Impact Resistance:** PET is known for its ability to absorb energy from impacts without shattering. This is particularly important for containers that may be dropped or subjected to rough handling. - **Chemical Resistance:** PET is resistant to many chemicals, making it suitable for storing a variety of liquids without degrading. - **Transparency:** PET can be made clear, which is aesthetically pleasing for consumers and allows for visibility of the contents. **2. Why Other Options Are Incorrect:** - **B. Polystyrene (PS):** - **Properties:** Polystyrene is a versatile plastic but is generally more brittle than PET. It is often used for disposable cutlery, foam packaging, and insulation materials. - **Limitations:** While it can be molded into various shapes, it does not have the same level of impact resistance or strength as PET, making it less suitable for bottles that need to endure physical stress. - **C. Polyvinyl chloride (PVC):** - **Properties:** PVC is a strong plastic that is often used in construction (like pipes) and medical devices. It can be rigid or flexible depending on how it is processed. - **Limitations:** While PVC is durable, it is not typically used for food and beverage containers due to concerns about leaching harmful chemicals. Its rigidity also makes it less suitable for applications requiring flexibility and impact resistance. - **D. Polypropylene (PP):** - **Properties:** Polypropylene is known for its toughness and resistance to fatigue. It is often used in containers, automotive parts, and textiles. - **Limitations:** While PP has good chemical resistance and is more flexible than PET, it does not have the same level of clarity and strength under pressure, making it less ideal for clear beverage bottles. **3. Summary of Key Points:** - **Strength and Impact Resistance:** PET is specifically designed to handle the stresses of containing liquids, especially carbonated beverages. - **Chemical and Thermal Stability:** PET maintains its integrity when in contact with various substances, making it a safe choice for food and drink. - **Market Preference:** PET is widely accepted and preferred in the beverage industry, leading to its extensive use in plastic bottles. ### Revision Summary: - **PET is the preferred polymer for plastic bottles due to its strength and impact resistance.** - **Polystyrene is brittle and not suitable for high-stress applications.** - **PVC is not commonly used for food containers due to safety concerns.** - **Polypropylene, while tough, lacks the clarity and pressure resistance of PET.** This comprehensive understanding of the properties and applications of these polymers will help you in identifying the right materials for various uses in chemistry and materials science.